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Jang SH, Kim SH, Seo JP. Long-term recovery from a minimally responsive state with recovery of an injured ascending reticular activating system: A case report. Medicine (Baltimore) 2021; 100:e23933. [PMID: 33655907 PMCID: PMC7939211 DOI: 10.1097/md.0000000000023933] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/26/2020] [Indexed: 01/04/2023] Open
Abstract
We report on a patient with hypoxic-ischemic brain injury (HI-BI) who showed recovery from a minimally consciousness state over 6 years concurrent with recovery of an injured ascending reticular activating system (ARAS), which was demonstrated on diffusion tensor tractography (DTT).A 31-year-old female patient, who suffered from HI-BI, showed impaired consciousness with a minimally conscious state: intermittently obeying simple motor tasks, such as "please grasp my hand." Her consciousness showed recovery with the passage of time; rapid recovery was observed during the recent 2 years.In the upper ARAS, the neural connectivity to both the basal forebrain and prefrontal cortex had increased on 8-year DTT compared with 1.5-year DTT. In the lower dorsal and ventral ARAS, no significant change was observed between 1.5 and 8 years DTTs.Recovery of an injured ARAS was demonstrated in a patient who showed recovery from a minimally consciousness state over 6 years following HI-BI. Our results suggest the brain target areas for recovery of impaired awareness in patients with disorders of consciousness.
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Affiliation(s)
- Sung Ho Jang
- Department of Physical Medicine and Rehabilitation
| | - Seong Ho Kim
- Department of Neurosurgery, College of Medicine, Yeungnam University, Gyeongsan-si, Gyeongsangbuk-do
| | - Jeong Pyo Seo
- Department of Physical Therapy, College of Health Sciences, Dankook University, Cheonan, Chungnam, Republic of Korea
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Engmann AK, Bizzozzero F, Schneider MP, Pfyffer D, Imobersteg S, Schneider R, Hofer AS, Wieckhorst M, Schwab ME. The Gigantocellular Reticular Nucleus Plays a Significant Role in Locomotor Recovery after Incomplete Spinal Cord Injury. J Neurosci 2020; 40:8292-8305. [PMID: 32978289 PMCID: PMC7577599 DOI: 10.1523/jneurosci.0474-20.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 09/14/2020] [Accepted: 09/18/2020] [Indexed: 11/21/2022] Open
Abstract
Traditionally, the brainstem has been seen as hardwired and poorly capable of plastic adaptations following spinal cord injury (SCI). Data acquired over the past decades, however, suggest differently: following SCI in various animal models (lamprey, chick, rodents, nonhuman primates), different forms of spontaneous anatomic plasticity of reticulospinal projections, many of them originating from the gigantocellular reticular nucleus (NRG), have been observed. In line with these anatomic observations, animals and humans with incomplete SCI often show various degrees of spontaneous motor recovery of hindlimb/leg function. Here, we investigated the functional relevance of two different modes of reticulospinal fiber growth after cervical hemisection, local rewiring of axotomized projections at the lesion site versus compensatory outgrowth of spared axons, using projection-specific, adeno-associated virus-mediated chemogenetic neuronal silencing. Detailed assessment of joint movements and limb kinetics during overground locomotion in female adult rats showed that locally rewired as well as compensatory NRG fibers were responsible for different aspects of recovered forelimb and hindlimb functions (i.e., stability, strength, coordination, speed, or timing). During walking and swimming, both locally rewired as well as compensatory NRG plasticity were crucial for recovered function, while the contribution of locally rewired NRG plasticity to wading performance was limited. Our data demonstrate comprehensively that locally rewired as well as compensatory plasticity of reticulospinal axons functionally contribute to the observed spontaneous improvement of stepping performance after incomplete SCI and are at least partially causative to the observed recovery of function, which can also be observed in human patients with spinal hemisection lesions.SIGNIFICANCE STATEMENT Following unilateral hemisection of the spinal cord, reticulospinal projections are destroyed on the injured side, resulting in impaired locomotion. Over time, a high degree of recovery can be observed in lesioned animals, like in human hemicord patients. In the rat, recovery is accompanied by pronounced spontaneous plasticity of axotomized and spared reticulospinal axons. We demonstrate the causative relevance of locally rewired as well as compensatory reticulospinal plasticity for the recovery of locomotor functions following spinal hemisection, using chemogenetic tools to selectively silence newly formed connections in behaviorally recovered animals. Moving from a correlative to a causative understanding of the role of neuroanatomical plasticity for functional recovery is fundamental for successful translation of treatment approaches from experimental studies to the clinics.
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Affiliation(s)
- Anne K Engmann
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Flavio Bizzozzero
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Marc P Schneider
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Dario Pfyffer
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Stefan Imobersteg
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Regula Schneider
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Anna-Sophie Hofer
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Martin Wieckhorst
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
| | - Martin E Schwab
- Department of Health Sciences and Technology, ETH Zurich, Brain Research Institute, University of Zurich, 8057 Zurich, Switzerland
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Abstract
RATIONALE We report on a stroke patient who showed restoration of discontinued corticoreticular pathways (CRPs) on serial diffusion tensor tractography (DTT) concurrent with recovery of gait disturbance following shunt operation for hydrocephalus. PATIENT CONCERNS A 67-year-old female patient underwent stereotactic drainage for management of intraventricular hemorrhage due to a rupture of the left posterior communicating artery. DIAGNOSES After 4 weeks from onset, the patient exhibited quadriparesis with more severe weakness in the proximal muscles and could not even stand or walk. She underwent comprehensive rehabilitation for 3 weeks. Her quadriparesis, as a result of hydrocephalus, did not improve significantly. INTERVENTIONS On the pre-op DTT, discontinuations (the right CRP: at subcortical white matter level, and the left CRP: at the midbrain level) of the CRP fibers from the premotor cortex were observed in both hemispheres. OUTCOMES She underwent a ventriculo-peritoneal shunt operation and her quadriparesis improved, especially the proximal muscles. Consequently, she could walk with mild assistance on an even floor at 5 days and walk on stairs at 4 weeks after the shunt operation. On the post-op DTT, the discontinued CRP fibers were elongated to the premotor cortex in both hemispheres. LESSONS Restoration of discontinued CRPs concurrent with recovery of gait disturbance following shunt operation for hydrocephalus was demonstrated in a stroke patient.
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Affiliation(s)
- Sung Ho Jang
- Department of Physical Medicine and Rehabilitation
| | - Chul Hoon Chang
- Department of Neurosurgery, College of Medicine, Yeungnam University, Daegu, Republic of Korea
| | - Young Jin Jung
- Department of Neurosurgery, College of Medicine, Yeungnam University, Daegu, Republic of Korea
| | - You Sung Seo
- Department of Physical Medicine and Rehabilitation
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Meinck HM. [Myoclonus as a movement disorder]. Nervenarzt 2017; 88:1133-1140. [PMID: 28852800 DOI: 10.1007/s00115-017-0399-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Myoclonus is often a diagnostic and therapeutic challenge due to its broad phenomenological variability and limited therapeutic options. This article gives a short survey and characterizes in detail two common types of myoclonus, cortical myoclonus and reticular reflex myoclonus. Clinical testing and electrophysiological investigations provide relevant local diagnostic indications for the generating structure(s). Such indications would influence not only the strategies of neuroimaging and laboratory investigations aimed at clarifying the underlying cause but also the selection of drugs to suppress myoclonus.
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Affiliation(s)
- H-M Meinck
- Neurologische Klinik, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.
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Golovchenko IV, Hayday MI. CORRELATION INDICES OF CEREBRAL HEMODYNAMICS AND ELECTRICAL ACTIVITY IN CHILDREN WITH IMPAIRED MOTOR SKILLS. ACTA ACUST UNITED AC 2016. [PMID: 29537203 DOI: 10.15407/fz62.01.074] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The correlations between the indicators of cerebral hemodynamics and electrical activity in children with impaired motor skills of central origin (children with cerebral palsy) were investigated. There is established a high number of links between indicators of rheoencephalogram (REG) and electroencephalogram (EEG) in the left cerebral hemisphere than in the right. In frontomastoidal allocation 19 correlations and in occipitomastoidal - 59 links. We suppose that poor circulation in vertebroplasty-basilar system leads to the defeat of the brain stem, which, with afferent pathways of the reticular formation, connects the thalamus with the cortex. In the reticular formation there is an inhibition of ascending activators influences, which eland to decreasing of the cortex is tonus. You can talk about the functional immaturity of the system of nonspecific activation by the reticular formation of the brain stem. Children with violation of motor activity had significantly more negative and positive significant and high correlation among the existing indicators of electric brain activity and cerebral hemodynamics, in our opinion, is due to the development of interconnection compensation that is carried out by adjustment of the functional systems and the formation of new forms of adaptive responses in conditions of disontogenetik. Feature correlation pattern of the EEG, of children with disorders of motor activity, is associated with a significantly great number of high and significant correlations between measures of electrical brain activity in the δ- and q- rhythms, especially in the temporal areas of the cerebral cortex. According to visual analysis of EEG there is revealed a common manifestation of changes of bioelectric brain activity in children with disorders of motor activity. This is manifested in the development of paroxysmal activity of action potentials of θ- and δ-rhythms with the focus of activity in the anterior areas of the cerebral cortex; the formation of a mosaic representation of the θ-rhythms in temporal areas; the presence of hypersynchronous a-paroxysms in the posterior areas of the cerebral cortex. The given facts testify to activation of mechanisms of limbic-neocortical systems and synchronizing influences of the reticular formation of the stem and diencephalic structures. There is also detected greater number of correlations when occipitomastoidal registration was lone it reflects compensatory redistribution of cerebral blood flow over the affected structures of brain stem structures that are associated with the provision of cortical functions.
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Voĭshenkov VB, Kartashev AV. [Dysfunction of the reticular formation in brain tumors and paraneoplastic involvement of the central nervous system]. Vopr Onkol 2013; 59:682-687. [PMID: 24624774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
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Abstract
Neurons in the caudalmost ventrolateral medulla (cmVLM) respond to noxious stimulation. We previously have shown most efferent projections from this locus project to areas implicated either in the processing or modulation of pain. Here we show the cmVLM of the rat receives projections from superficial laminae of the medullary dorsal horn (MDH) and has neurons activated with capsaicin injections into the temporalis muscle. Injections of either biotinylated dextran amine (BDA) into the MDH or fluorogold (FG)/fluorescent microbeads into the cmVLM showed projections from lamina I and II of the MDH to the cmVLM. Morphometric analysis showed the retrogradely-labeled neurons were small (area 88.7 µm(2)±3.4) and mostly fusiform in shape. Injections (20-50 µl) of 0.5% capsaicin into the temporalis muscle and subsequent immunohistochemistry for c-Fos showed nuclei labeled in the dorsomedial trigeminocervical complex (TCC), the cmVLM, the lateral medulla, and the internal lateral subnucleus of the parabrachial complex (PBil). Additional labeling with c-Fos was seen in the subnucleus interpolaris of the spinal trigeminal nucleus, the rostral ventrolateral medulla, the superior salivatory nucleus, the rostral ventromedial medulla, and the A1, A5, A7 and subcoeruleus catecholamine areas. Injections of FG into the PBil produced robust label in the lateral medulla and cmVLM while injections of BDA into the lateral medulla showed projections to the PBil. Immunohistochemical experiments to antibodies against substance P, the substance P receptor (NK1), calcitonin gene regulating peptide, leucine enkephalin, VRL1 (TPRV2) receptors and neuropeptide Y showed that these peptides/receptors densely stained the cmVLM. We suggest the MDH- cmVLM projection is important for pain from head and neck areas. We offer a potential new pathway for regulating deep pain via the neurons of the TCC, the cmVLM, the lateral medulla, and the PBil and propose these areas compose a trigeminoreticular pathway, possibly the trigeminal homologue of the spinoreticulothalamic pathway.
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Affiliation(s)
- W Michael Panneton
- Department of Pharmacological and Physiological Science, St. Louis University School of Medicine, St. Louis, Missouri, United States of America.
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Garzón García M. [Neuroanatomic bases of hypocretin actions on the ascending reticular activating system: a contribution to narcolepsy physiopathology]. An R Acad Nac Med (Madr) 2010; 127:327-346. [PMID: 21877413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The present study describes at the ultrastructural level the hypocretinergic innervation of brainstem reticular formation neurons that project to the medial frontal cortex in the rat. In addition, we assess, by using dual immunofluorescence techniques, the proportion of those reticular neurons containing specific neurotransmitters. Our results indicate that hypocretinergic axons make asymmetric synapses with neurons within the locus coeruleus, ventral tegmental area, dorsal raphe nucleus and laterodorsal tegmental nucleus that target the medial frontal cortex, Hypocretins could facilitate wakefulness and cortical activation, therefore, by activation of those neurons with cortical projections in these four reticular nuclei.
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9
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Starosel'tseva NG. [Characteristics of spino-bulbar-spinal reflex in central nervous system pathology]. Zh Nevrol Psikhiatr Im S S Korsakova 2010; 110:61-66. [PMID: 21322128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Baracskay P, Kiglics V, Kékesi KA, Juhász G, Czurkó A. Status epilepticus affects the gigantocellular network of the pontine reticular formation. BMC Neurosci 2009; 10:133. [PMID: 19912649 PMCID: PMC2781816 DOI: 10.1186/1471-2202-10-133] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2009] [Accepted: 11/13/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The impairment of the pontine reticular formation (PRF) has recently been revealed to be histopathologically connected with focal-cortical seizure induced generalized convulsive status epilepticus. To elucidate whether the impairment of the PRF is a general phenomenon during status epilepticus, the focal-cortical 4-aminopyridine (4-AP) application was compared with other epilepsy models. The presence of "dark" neurons in the PRF was investigated by the sensitive silver method of Gallyas in rats sacrificed at 3 h after focal 4-AP crystal or systemic 4-AP, pilocarpine, or kainic acid application. The behavioral signs of the developing epileptic seizures were scored in all rats. The EEG activity was recorded in eight rats. RESULTS Regardless of the initiating drug or method of administration, "dark" neurons were consistently found in the PRF of animals entered the later phases of status epilepticus. EEG recordings demonstrated the presence of slow oscillations (1.5-2.5 Hz) simultaneously with the appearance of giant "dark" neurons in the PRF. CONCLUSION We argue that the observed slow oscillation corresponds to the late periodic epileptiform discharge phase of status epilepticus, and that the PRF may be involved in the progression of status epilepticus.
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Affiliation(s)
- Péter Baracskay
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
- Institute of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary
| | - Viola Kiglics
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Katalin A Kékesi
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
- Department of Physiology and Neurobiology, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Gábor Juhász
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - András Czurkó
- Laboratory of Proteomics, Institute of Biology, Eötvös Loránd University, H-1117 Budapest, Hungary
- Institute of Medical Chemistry, University of Szeged, H-6720 Szeged, Hungary
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Prieto-Gomez B, Dafny N. Effects of Morphine on: Spontaneous, Dorsal Raphe, Spinal Tract of Trigeminal Nucleus, Medial Lemniscus and Reticular Lateral Magnocellular Evoked Responses of Hypothalamic Units, in Naive and Morphine Physically Dependent Rats. Int J Neurosci 2009; 23:131-45. [PMID: 6541213 DOI: 10.3109/00207458408985355] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The spontaneous activity and the inputs to the medial basal hypothalamus (MBH) following dorsal raphe (DR), spinal tract of the trigeminal nerve (SpV), medial lemniscus (ML), reticular lateral magnocellular nucleus ( RLM ) and acoustic (Ac) stimulation and the effects of morphine and the opioid antagonist, naloxone, on these inputs, were investigated in morphine-naive and morphine-dependent animals. The observations were obtained in freely behaving animals previously implanted with permanent electrodes. The spontaneous activity of MBH neurons exhibits heterogenic spontaneous firing rates. This spontaneous activity is affected by acute and chronic morphine treatment. The MBH neuronal population exhibits neurophysiological patterns of tolerance of morphine dependence and withdrawal. The central input exerts a marked influence on MBH neurons in both naive and morphine-dependent animals. These inputs are modified by morphine challenge dose in both preparations, i.e., in morphine-naive and morphine-dependent animals, and are reversed by naloxone. The DR and Ac inputs affect the MBH neuronal activity differently from that observed following SpV, ML and RLM stimuli. The effects of morphine and naloxone on the DR and Ac input in morphine-naive and morphine-dependent animals differ from those observed following SpV, ML and RLM inputs. The MBH neurons exhibited a high percentage of convergence to Ac, DR, SpV, ML and RLM stimulation.
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12
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Mistovich JJ, Krost WS, Limmer DD. Beyond the basics: interpreting altered mental status assessment findings. EMS Mag 2008; 37:90-99. [PMID: 18814744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
EMS providers frequently encounter patients who are not alert and present with an altered mental status, meaning their level of brain function is in question. Various physical examination techniques are employed during the assessment to determine the level of cerebral function and integrity of the brainstem. It is important to understand the limitations of these techniques, as well as potential findings that may cause you to erroreously interpret, re port and document the level of brain function. This information is often used to identify trends to determine if the patient's condition is deteriorating, remaining the same or improving.
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13
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Abstract
What are the neuroanatomical structures involved in repetitive yawning during stroke?
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Owen SLF, Green AL, Davies P, Stein JF, Aziz TZ, Behrens T, Voets NL, Johansen-Berg H. Connectivity of an effective hypothalamic surgical target for cluster headache. J Clin Neurosci 2007; 14:955-60. [PMID: 17689083 DOI: 10.1016/j.jocn.2006.07.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2006] [Revised: 07/06/2006] [Accepted: 07/14/2006] [Indexed: 11/19/2022]
Abstract
The purpose of this study was to look at the connectivity of the posterior inferior hypothalamus in a patient implanted with a deep brain stimulating electrode using probabilistic tractography in conjunction with postoperative MRI scans. In a patient with chronic cluster headache we implanted a deep brain stimulating electrode into the ipsilateral postero-medial hypothalamus to successfully control his pain. To explore the connectivity, we used the surgical target from the postoperative MRI scan as a seed for probabilistic tractography, which was then linked to diffusion weighted imaging data acquired in a group of healthy control subjects. We found highly consistent connections with the reticular nucleus and cerebellum. In some subjects, connections were also seen with the parietal cortices, and the inferior medial frontal gyrus. Our results illustrate important anatomical connections that may explain the functional changes associated with cluster headaches and elucidate possible mechanisms responsible for triggering attacks.
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Affiliation(s)
- S L F Owen
- University Laboratory of Physiology, University of Oxford, Oxford, UK
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Buck BJ, Kerman IA, Burghardt PR, Koch LG, Britton SL, Akil H, Watson SJ. Upregulation of GAD65 mRNA in the medulla of the rat model of metabolic syndrome. Neurosci Lett 2007; 419:178-83. [PMID: 17490814 PMCID: PMC1945106 DOI: 10.1016/j.neulet.2007.04.042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2007] [Revised: 04/17/2007] [Accepted: 04/20/2007] [Indexed: 02/07/2023]
Abstract
Metabolic syndrome is characterized by obesity, elevated blood pressure (BP), insulin resistance, and hypercholesterolemia. Recently an animal model of this disorder has been proposed in rats selectively bred based on their performance on a treadmill-running task. Accordingly, low capacity runner (LCR) rats exhibited all of the diagnostic criteria for metabolic syndrome, including elevated BP, as compared to their high capacity runner (HCR) counterparts [U. Wisløff, S.M. Najjar, O. Ellingsen, P.M. Haram, S. Swoap, Q. Al-Share, M. Fernstrom, K. Rezaei, S.J. Lee, L.G. Koch, S.L. Britton, Cardiovascular risk factors emerge after artificial selection for low aerobic capacity, Science 307 (2005) 418-420]. Previous studies have highlighted the importance of GABAergic neurotransmission in the medullary cardiovascular-regulatory areas in the central control of BP. Thus, we hypothesized a dysregulation in GABAergic transmission in the medullary cardiovascular-regulatory nuclei of LCR rats. To begin testing this hypothesis we carried out experiments examining expression of the GABA synthetic enzymes, GAD65 and GAD67, mRNAs in the two rat strains via radioactive in situ hybridization. Our results showed GAD65 and GAD67 mRNAs were widely expressed throughout the brainstem; quantification revealed increased GAD65 mRNA expression in LCR animals in the caudal nucleus tractus solitarius (NTS) and rostral ventrolateral medulla (VLM) as compared to HCR rats. Conversely, no differences in the expression of GAD67 were detected in these regions. These data are consistent with the notion of altered GABAergic neurotransmission in the NTS and VLM in metabolic syndrome, and point to the importance of these regions in cardiovascular regulation.
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Affiliation(s)
- Bradley J Buck
- Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109, USA
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Abstract
PURPOSE Lateralized clonic jerks of the extremities during epileptic seizures usually arise from the contralateral rolandic cortex. In our exceptional case one-sided extremity twitches related to epileptiform activity in the ipsilateral frontal lobe. METHODS Case study with clinical-electroencephalographic correlation. RESULTS A 47-year-old man suffered destruction of most of his right cerebral hemisphere, including the perirolandic region. Epilepsia partialis continua (EPC) ensued, with clonic jerks of the proximal right upper and lower limbs temporally related to periodic lateralized epileptiform discharges (PLEDs) from the parasagittal region of the right frontal lobe with a variable time interval over 100 ms. Sectioning of the subcortical callosal and projection connections of the frontal lobe abolished the clonic jerks. CONCLUSIONS We propose the ipsilateral EPC arose from projections from the supplementary motor region to the medullary reticular formation to account for the long and variable latency between PLEDs and jerks.
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Affiliation(s)
- G Bryan Young
- Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada.
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Abstract
OBJECTIVE High-density EEG during sleep represents a powerful new tool to reveal potential abnormalities in rhythm-generating mechanisms while avoiding confounding factors associated with waking activities. As a first step in this direction, the authors employed high-density EEG to explore whether sleep rhythms differ between schizophrenia subjects, healthy individuals, and a psychiatric control group with a history of depression. METHOD Healthy comparison subjects (N=17), medicated schizophrenia patients (N=18), and subjects with a history of depression (N=15) were recruited. Subjects were recorded during the first sleep episode of the night with a 256-electrode high-density EEG. Recordings were analyzed for changes in EEG power spectra, power topography, and sleep-specific cortical oscillations. RESULTS The authors found that the schizophrenia group had a significant reduction in centroparietal EEG power, from 13.75 to 15.00 Hz, in relation to both the comparison and depression groups. No significant difference in EEG power between the comparison and depression groups was identified. The authors also found a decrease in sleep spindle number, amplitude, duration, and integrated spindle activity in schizophrenia patients. Furthermore, integrated spindle activity had an effect size corresponding to 93.0% or 90.2% separation of the schizophrenia from the comparison or depression group. CONCLUSIONS Sleep spindles are generated by the thalamic reticular nucleus in conjunction with specific thalamic nuclei and are modulated by corticothalamic and thalamocortical connections. The deficit in sleep spindles in schizophrenia subjects may reflect dysfunction in thalamic-reticular and thalamocortical mechanisms and could represent a biological marker of illness.
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Affiliation(s)
- Fabio Ferrarelli
- University of Wisconsin, Department of Psychiatry, 6001 Research Park Blvd., Madison, WI 53719, USA
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Dubas F. [Nontraumatic coma]. Rev Prat 2007; 57:321-6. [PMID: 17578035] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Affiliation(s)
- Frédéric Dubas
- Département de neurologie, centre hospitalier universitaire, 49033 Angers.
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20
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Abstract
A 38-year-old immunocompetent man presented with a horizontal supranuclear gaze palsy as the only neurologic manifestation of a pontine tuberculoma. Although a biopsy of the brain lesion was not performed, it was attributed to tuberculosis because of chest x-ray evidence. The patient was given empirical anti-tuberculous therapy. After one month, the gaze palsy had fully recovered and repeat MRI showed a decrease in the size of the lesion. This is the first reported case of supranuclear gaze palsy without diplopia as a manifestation of a tuberculous brain stem lesion.
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Affiliation(s)
- Rohit Saxena
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.
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21
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Nedostup AV, Vasiukov SS, Gordeev SA, Fedorova VI. [Clinico-neurophysiological features of the course of the disease in patients with paroxysmal atrial fibrillation]. Klin Med (Mosk) 2007; 85:34-8. [PMID: 17882807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The subjects of the study were 32 patients with paroxysmal atrial fibrillation (AF) and 19 ':ealthy individuals using a clinical and neurophysiological method of toposelective mapping of electroencephalogram (EEG). EEG was done during the inter-attack, pre-attack, and post-attack periods, as well as during a paroxysm. During the inter-attack period, the patients had a lower beta-rhythm power vs. the healthy controls, while there were no significant differences between them in the power of alpha- and beta-activity. Before an attack, the patients had a significant increase in beta, alpha-, and theta-range power, reflecting the intensification of the activity of the metaencephalic reticular formation, thalamocortical, and hypothalamosepto-hyppocampal systems, respectively. During an AF paroxysm, the activity of the thalamocortical and reticular systems was lowered, while the activity of the hypothalamo-hyppocampal system further increased. After an attack, the activity of all the mentioned systems went down to the initial state of the "optimal" brain functioning after an excessive excitation. It is assumed that generalized one-way direction of EEG changes before an attack reflects tensed functioning of practically all activation systems, which increases the probability of a "breakdown" in a form of an AF paroxysm. The data of the study evidence a cyclic character of the disease and stresses an important role in AF pathogenesis played by disturbances associated with the functional condition of non-specific temporal-limbic and reticular brain structures, especially in patients without organic myocardial alterations.
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Gordeev SA. [Clinical and psychophysiological study of patients with panic attacks with or without agoraphobic disorders]. Zh Nevrol Psikhiatr Im S S Korsakova 2007; 107:54-58. [PMID: 18379505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Seventy-seven patients with panic attacks (PA) with or without agoraphobic disorders and 28 healthy controls have been studied using clinico-neurological and psychological methods as well as EEG and auditory event-related evoked potentials (EP) recording. PA patients with agoraphobic disorders featured a significant decrease of density of a-rhythm power and an increase of b-rhythm power in the right hemisphere that reflected a substantial activation of the ascending mesencephalic reticular formation. At the same time, a significant increase of q-rhythm power in temporal areas of the right hemisphere was characteristic of patients without agoraphobia that suggested reinforcement of activity of temporal-limbic structures. Patients with agoraphobia demonstrated lower P300 wave amplitude, marked disturbances of its habituation, more impaired attention and higher level of anxiety and depression as compared to those without agoraphobia.
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Kaddumi EG, Hubscher CH. Changes in rat brainstem responsiveness to somatovisceral inputs following acute bladder irritation. Exp Neurol 2006; 203:349-57. [PMID: 17010973 DOI: 10.1016/j.expneurol.2006.08.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2006] [Revised: 07/14/2006] [Accepted: 08/17/2006] [Indexed: 12/27/2022]
Abstract
A number of clinical studies indicate the coexistence of multiple chronic pelvic diseases and pain syndromes. An association between various conditions related to the pelvic viscera may relate to a high degree of central visceral convergence, which is a requisite for the cross-organ coordination that is necessary for their normal functions. In the present study, a population of neurons receiving a high degree of somatovisceral convergence (those in the medullary reticular formation--MRF) was targeted in order to examine the effect of infusing a chemical irritant into one organ on the responsiveness of convergent inputs from various visceral and somatic regions of the body, using electrophysiological techniques. Acute irritation of the urinary bladder (UB) with 2% acetic acid significantly decreased the percentage of convergent MRF neuronal responses to UB distention and urethral infusion and significantly increased the percentage responding to whole body, mainly due to stimulation of the face. Irritation also produced a significant increase in the response duration of MRF neurons to distention of colon as well as the bladder (for those few UB responses that still remained). These results indicate that a pelvic/visceral pathology confined to one organ can affect at least some of the convergent responses from other regions of the body. The findings suggest that MRF neurons contribute to the cross-talk between different regions of the body under both normal and pathological conditions.
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Affiliation(s)
- Ezidin G Kaddumi
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, KY 40292, USA
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24
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Abstract
To determine whether differential sympathetic nerve responses to hypoxia are explained by opposing effects of hypoxia upon sympathetic premotor neurons in the rostral ventrolateral medulla (RVLM), the cardiac sympathetic nerve and the renal sympathetic nerve were recorded in anesthetized and vagotomized rabbits. Renal sympathetic nerve was activated by the injection of sodium cyanide solution close to the bifurcation of the common carotid artery and/or by inhalation of hypoxic gas (3% oxygen-97% nitrogen). On the other hand, cardiac sympathetic nerve was inhibited by these stimuli. Barosensitive (inhibited by the stimulation of baroreceptor afferents) reticulospinal (antidromically activated by the stimulation of the spinal cord) neurons in the RVLM were divided into three groups according to their responses to hypoxic stimulation: neurons (Type I, n = 25), the activity of which was inhibited by the injection of sodium cyanide solution close to the bifurcation of the common carotid artery and/or by inhalation of hypoxic gas, neurons (Type II, n = 99), the activity of which was facilitated by the same stimulation, and neurons (Type III, n = 11), the activity of which was not changed. These data indicated that the differential responses of cardiac and renal sympathetic nerves might be due to opposing effects of hypoxia on individual RVLM neurons.
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Affiliation(s)
- Tadachika Koganezawa
- Dept. of Physiology, Institute of Basic Medical Sciences, Graduate School of Comprehensive Human Sciences, Univ. of Tsukuba, 1-1-1 Tennodai, Tsukuba Ibaraki 305-8575, Japan
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Abstract
Exaggerated startle is an uncommon feature of various neurological diseases, but is still lacking precise analysis in many of them. So far, electrophysiologic and cinematographic analyses allow discriminating two main subtypes. The prototype of primary exaggerated startle is hereditary hyperekplexia, a well-studied disorder of the inhibitory glycine receptor and thus of the neuronal Cl- channel. The involuntary jerking in hereditary hyperekplexia is considered a reticular reflex myoclonus. The prototype of primary normal startle with secondary abnormalities is startle epilepsy where a surprise stimulus typically provokes a normal startle, which in turn initiates a focal (most often frontal lobe) seizure with tonic posturing of the limbs. Clinical differential diagnosis between both subtypes may be difficult in individual cases, but there are abnormalities in clinical and neurophysiologic reflex testing, which need, however, broad validation.
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Affiliation(s)
- H-M Meinck
- Neurologische Universitätsklinik, Im Neuenheimerfeld 400, D 69120 Heidelberg, Germany.
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Abstract
Myoclonus may be generated by any area in the central nervous system. Finding its generator is helpful in the diagnostic process. Although clinical features have to be carefully analyzed as they may give a first idea, neurophysiologic study of myoclonus provides the most important clues for the determination of the generator. Surface electromyography (EMG) allows analyzing the recruitment order in generalized myoclonus, thereby suggesting either a cortical, brainstem, or spinal origin. It also reveals whether myoclonus is positive (jerks that are caused by muscle activation) or negative (jerks that are caused by brief muscle inhibition). In non-generalized myoclonus the EMG burst duration gives an idea of the level of the generator. Repetitive peripheral nerve stimulation is required to record somatosensory evoked potentials (SEPs) as well as long latency reflexes (LLR), especially the C reflex. The presence of giant cortical SEPs is an indirect argument for cortical myoclonus. Similarly the existence of LLR at rest orientates towards cortical reflex (sensitive to sensory stimuli) myoclonus. Finally EEG-EMG polygraphy is the only test which is able to prove directly the cortical origin of myoclonus. This is the case when focal cortical events precede myoclonus with a fixed delay. These premyoclonic cortical potentials may either be seen directly on raw recordings or require the use of jerk-locked back averaging (JLBA). This technique allows the averaging of the EEG prior to myoclonus onset (as determined by EMG) in order to reveal a premyoclonic spike that otherwise would remain undetected in the global EEG.
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Affiliation(s)
- F Cassim
- Service de neurophysiologie clinique, EA 2683, hôpital Salengro, CHU, 59037 Lille cedex, France.
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de Oliveira RC, de Oliveira R, Ferreira CMDR, Coimbra NC. Involvement of 5-HT(2) serotonergic receptors of the nucleus raphe magnus and nucleus reticularis gigantocellularis/paragigantocellularis complex neural networks in the antinociceptive phenomenon that follows the post-ictal immobility syndrome. Exp Neurol 2006; 201:144-53. [PMID: 16842781 DOI: 10.1016/j.expneurol.2006.03.033] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Revised: 03/17/2006] [Accepted: 03/31/2006] [Indexed: 12/30/2022]
Abstract
The post-ictal immobility syndrome is followed by a significant increase in the nociceptive thresholds in animals and men. In this interesting post-ictal behavioral response, endogenous opioid peptides-mediated mechanisms, as well as cholinergic-mediated antinociceptive processes, have been suggested. However, considering that many serotonergic descending pathways have been implicated in antinociceptive reactions, the aim of the present work is to investigate the involvement of 5-HT(2)-serotonergic receptor subfamily in the post-ictal antinociception. The analgesia was measured by the tail-flick test in seven or eight Wistar rats per group. Convulsions were followed by statistically significant increase in the tail-flick latencies (TFL), at least for 120 min of the post-ictal period. Male Wistar rats were submitted to stereotaxic surgery for introduction of a guide-cannula in the rhombencephalon, aiming either the nucleus raphe magnus (NRM) or the gigantocellularis complex. In independent groups of animals, these nuclei were neurochemically lesioned with a unilateral microinjection of ibotenic acid (1.0 microg/0.2 microL). The neuronal damage of either the NRM or nucleus reticularis gigantocellularis/paragigantocellularis complex decreased the post-ictal analgesia. Also, in other independent groups, central administration of ritanserin (5.0 microg/0.2 microL) or physiological saline into each of the reticular formation nuclei studied caused a statistically significant decrease in the TFL of seizing animals, as compared to controls, in all post-ictal periods studied. These results indicate that serotonin input-connected neurons of the pontine and medullarly reticular nuclei may be involved in the post-ictal analgesia.
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Affiliation(s)
- Rithiele Cristina de Oliveira
- Laboratory of Neuroanatomy and Neuropsychobiology, Department of Pharmacology, School of Medicine of Ribeirão Preto of the University of São Paulo (USP), Av. dos Bandeirantes 3900, Ribeirão Preto (SP) 14049-900, Brazil
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Protopopescu X, Pan H, Tuescher O, Cloitre M, Goldstein M, Engelien A, Yang Y, Gorman J, LeDoux J, Stern E, Silbersweig D. Increased brainstem volume in panic disorder: a voxel-based morphometric study. Neuroreport 2006; 17:361-3. [PMID: 16514359 DOI: 10.1097/01.wnr.0000203354.80438.1] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Neurocircuitry models of panic disorder have hypothesized that the panic attack itself stems from loci in the brainstem including the ascending reticular system and respiratory and cardiovascular control centers. Voxel-based morphometry with acobian modulation was used to examine gray matter volume changes in 10 panic disorder patients and 23 healthy controls. The panic disorder patients had a relatively increased gray matter volume in the midbrain and rostral pons of the brainstem. Increased ventral hippocampal and decreased regional prefrontal cortex volumes were also noted at a lower significance threshold. This finding has implications for pathophysiologic models of panic disorder, and provides structural evidence for the role of the brainstem in neurocircuitry models of panic disorder.
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Affiliation(s)
- Xenia Protopopescu
- Functional Neuroimaging Laboratory, Department of Psychiatry, Weill Medical College of Cornell University, New York, New York, USA
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Abstract
In this article, a preliminary conceptual framework is presented for exploring nursing interventions and research aimed at improving care of the unconscious brain-injured patient during the early subacute phase of brain injury. The cue-response framework presented is derived from multidisciplinary sources and has specific clinical relevance to critical care nurses caring for unconscious brain-injured patients. A key aspect of this framework is the attention focused on the timing of nursing interventions in response to how nurses interpret the physical, physiological, and secondary cues they observe when caring for comatose patients. A case exemplar is used to present one example of how this framework may be used in the clinical setting.
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Affiliation(s)
- DaiWai M Olson
- School of Nursing, The University of North Carolina at Chapel Hill, North Carolina 27712, USA.
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31
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Abstract
Supraspinal centres biphasically modulate spinal nociceptive transmission, including descending inhibition and facilitation. Recent studies have revealed that descending facilitatory modulation is a key mechanism underlying induction and maintenance of neuropathic and inflammatory pain. The anterior cingulate cortex (ACC) is not only involved in the transmission of pain sensation but also plays a role in processing pain-related emotion. The ACC also widely connects with relevant regions of the descending modulation system. Here we used electrophysiological and behavioural techniques to study the possible pathways behind the modulation of spinal nociceptive transmission from the ACC. C-fibre-evoked field potentials in the spinal dorsal horn were produced by electrical stimulation of the sciatic nerve at an intensity high enough to excite C fibres, and paw withdrawal latencies (PWLs) to noxious heating were recorded. The results showed that high-frequency tetanic electrical stimulation of the ACC both unilaterally enhanced the C-fibre-evoked field potentials in the spinal dorsal horn and bilaterally shortened PWLs, indicating a facilitation of spinal nociception. A similar effect was observed after microinjection of N-methyl-d-aspartic acid (NMDA; 10 nm, 1 microL) or homocysteic acid (HCA; 0.1 m, 1 microL) into the ACC. When the dorsal reticular nucleus (DRt) was electrolytically lesioned, ACC-induced facilitation of spinal nociception was blocked. These results imply that: (i) activation of the ACC may facilitate spinal nociception; (ii) NMDA receptors in the ACC may be involved in descending facilitation; and (iii) the DRt plays a crucial role in mediating ACC-induced facilitation of spinal nociception.
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Affiliation(s)
- Ling Zhang
- Institute of Neurobiology, Fudan University, Shanghai 200433, P R China
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Raisinghani M, Faingold CL. Pontine reticular formation neurons are implicated in the neuronal network for generalized clonic seizures which is intensified by audiogenic kindling. Brain Res 2005; 1064:90-7. [PMID: 16336948 DOI: 10.1016/j.brainres.2005.09.047] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2005] [Revised: 09/15/2005] [Accepted: 09/24/2005] [Indexed: 11/30/2022]
Abstract
The caudal pontine reticular formation nucleus (cPRF) is implicated in seizure propagation to the spinal cord in several forms of generalized convulsive seizures, including audiogenic seizures (AGS). Focal microinjection studies implicate cPRF as a requisite neuronal network site subserving generalized AGS in the moderate severity substrain of genetically epilepsy-prone rats (GEPR-3s). AGS in GEPR-3s culminate in generalized clonus, but daily repetition of AGS (AGS kindling) results in an additional seizure behavior, facial and forelimb (F and F) clonus, not seen prior to kindling. This study examined cPRF neuronal firing changes and seizure behaviors during AGS in GEPR-3s. We examined extracellular cPRF neuronal responses to acoustic stimuli (12 kHz) and observed neuronal firing during AGS. cPRF neurons exhibited onset responses to acoustic stimuli before and after AGS kindling. After AGS kindling, increased neuronal firing occurred, and response latencies were prolonged. Tonic neuronal firing occurred during generalized clonus, which changed to burst firing after AGS kindling. Burst firing also occurred during F and F clonus. Increased neuronal firing and the change from tonic to burst firing suggest that AGS kindling involves increased cPRF excitability. These data support an important role for cPRF neurons in generation of generalized clonus in unkindled GEPR-3s, which is increased by AGS kindling. The increased cPRF response latency might reflect a greater role of rostral components of the AGS neuronal network in transmission of acoustic responses to cPRF. This study also suggests that cPRF neurons may be involved in F and F clonus, which was unexpected since F and F clonus is thought to originate primarily in forebrain structures.
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Affiliation(s)
- Manish Raisinghani
- Department of Pharmacology, Southern Illinois University School of Medicine, PO Box 19629, Springfield, IL 62794-9629, USA
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33
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Abstract
In a patient-controlled study, the authors demonstrated a significantly higher prevalence of rostral ventrolateral medulla (VLM) compression in hypertensive patients with hemifacial spasm (HFS) compared with age-, sex-, race-, disease duration-, and disease severity-matched normotensive patients with HFS (p = 0.02). Hypertensive HFS patients were more likely to have a greater severity of neurovascular compression at the VLM compared with normotensive HFS patients (p = 0.008). VLM compression is associated with risk of hypertension in this study population.
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Affiliation(s)
- L L Chan
- Department of Diagnostic Radiology, Singapore General Hospital, Republic of Singapore
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Lin Y, Matsumura K, Kagiyama S, Fukuhara M, Fujii K, Iida M. Chronic administration of olmesartan attenuates the exaggerated pressor response to glutamate in the rostral ventrolateral medulla of SHR. Brain Res 2005; 1058:161-6. [PMID: 16143317 DOI: 10.1016/j.brainres.2005.07.070] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Revised: 07/29/2005] [Accepted: 07/29/2005] [Indexed: 02/07/2023]
Abstract
It has been shown that the pressor responses to microinjection of L-glutamate in the rostral ventrolateral medulla (RVLM) are augmented in spontaneously hypertensive rats (SHR), and that these augmented responses are not altered by chronic conventional antihypertensive treatment. The aim of the present study was to determine the effect of chronic oral treatment with a new angiotensin II type 1 (AT(1)) receptor antagonist, RNH-6270 (the active form of olmesartan medoxomil), on cardiovascular responses to excitatory amino acids in the RVLM of SHR. SHR (12 weeks old) were treated with RNH-6270 (30 mg/kg/day) or vehicle for 4 weeks. At 16 weeks of age, L-glutamate (2 nmol), N-methyl-D-aspartate (NMDA; an ionotropic glutamate receptor agonist (20 pmol)), or (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD; a metabotropic glutamate receptor agonist (1 nmol)) was microinjected into the RVLM of rats. The pressor responses to microinjection of L-glutamate or NMDA in the RNH-6270-treated SHR (+28.3 +/- 1.0 and +48.3 +/- 2.5 mm Hg, respectively) were significantly smaller than those in untreated SHR (+45.7 +/- 2.2 and +69.4 +/- 7.0 mm Hg, respectively, P < 0.05 each); however, they were still greater than those in the Wistar-Kyoto rats (+21.7 +/- 1.0 and +28.6 +/- 3.3 mm Hg, respectively, P < 0.05 each). In contrast, the augmented pressor responses to microinjection of (1S,3R)-ACPD in SHR were not affected by the RNH-6270 treatment. These results demonstrated that chronic oral treatment with RNH-6270, an AT(1) receptor antagonist, partly normalizes the pressor responses to L-glutamate or NMDA, but not (1S,3R)-ACPD, in the RVLM of SHR, suggesting that endogenous angiotensin II may be involved in the exaggerated pressor response to l-glutamate, probably through its ionotropic glutamate receptors.
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Affiliation(s)
- Yingzi Lin
- Department of Medicine and Clinical Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Okahashi Y, Kataoka H, Kawahara M, Tamaru T, Ueno S. A carrier of human T-lymphotropic virus type I with periodic limb movements progressing to myelopathy. Neurology 2005; 65:965-6. [PMID: 16186552 DOI: 10.1212/01.wnl.0000175985.33134.70] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Y Okahashi
- Department of Neurology, Nara Medical University, Kashihara, Nara 634-8522, Japan
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Abstract
STUDY OBJECTIVES This study was designed to show the influence of sleep deprivation on different types of saccadic eye movements. DESIGN Performance of saccadic eye movements was compared after normal sleep and sleep deprivation in a randomized, within-subjects paradigm. Parameters of voluntary and reflexive saccades were measured before and after experimental nights and after a night of recovery sleep. Additionally, subjects spent 1 adaptation night in the laboratory before the experiments. SETTING Experiments took place under controlled laboratory conditions. PARTICIPANTS Fifteen healthy male volunteers (aged 19-30 years). INTERVENTIONS Each subject participated in 1 night of sleep deprivation followed by a night of recovery sleep and, on another occasion, in 2 successive nights of undisturbed sleep. MEASUREMENTS AND RESULTS Horizontal prosaccades, antisaccades, and memory-guided saccades were recorded by means of electrooculography. They were analysed semiautomatically with respect to accuracy, peak velocity, and latency. Peak velocity was significantly reduced in all saccade tasks after 1 night of sleep deprivation but recovered after another night of sleep. Latency was prolonged after sleep deprivation only for memory-guided saccades; accuracy showed a decrease after 1 night without sleep only for prosaccades. CONCLUSIONS Sleep deprivation has a general impairing effect on the peak velocity of saccades, reflecting possible dysfunction at the level of the brainstem reticular formation. Deficits of accuracy and latency point to dysfunction of specific brain sites such as the supplementary eye field and cerebellum, whereas the cardinal functions of the frontal and parietal eye fields were not affected. These results suggest the possibility of measuring fatigue by means of saccadic parameters, especially saccadic peak velocity.
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Abstract
BACKGROUND Malformations of cortical development have characteristic interictal discharges, yet the mechanisms of generation of these discharges are not known in humans. Interictal discharges in malformations of cortical development were studied with EEG-fMRI. METHODS Six subjects with malformations of cortical development and seizures were studied using spike-triggered fMRI at 3 T. The blood oxygen level-dependent (BOLD) signal changes associated with interictal discharges were measured. RESULTS All subjects showed spike-related BOLD signal changes. In four subjects, the signal increases were seen in the lesion, and in four subjects, decreases were seen surrounding the lesion. Five subjects had BOLD signal changes at distant cortical sites and three had subcortical changes (basal ganglia, reticular formation, or thalamic). CONCLUSION BOLD signal changes may be directly correlated with overall synaptic activity. Changes were found in and around the lesion of malformations of cortical development and in distant cortical and subcortical structures. The results suggest that EEG-fMRI studies might help elucidate the mechanisms of epileptic discharges in humans.
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Affiliation(s)
- Paolo Federico
- Brain Research Institute, Heidelberg West, Victoria, Australia
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Abstract
The incidence of people surviving with traumatic brain injury is rising at a remarkable pace. Unfortunately, patients also experience some form of coma and significant deficits (ie, cognitive, functional, etc). The focus is shifting from saving these patients to trying to figure out what else can be done for them? In the past, patients were medically maintained, stabilized, and then sent to rehabilitation centers for coma stimulation, in the hope of waking up their reticular activating system. Today, healthcare professionals are being encouraged to research and explore the possibility of implementing structured coma stimulation programs as early as 72 hours postinjury in the intensive care unit. Starting early is of paramount importance to a patient's survival, quality of life, and overall long-term prognosis. The goal of this article is to educate healthcare professionals (in the hospital setting) about managing and implementing structured sensory stimulation sessions.
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Affiliation(s)
- Carolyn S Gerber
- Surgical Intensive Care Unit, Scripps Mercy Hospital, San Diego, CA 92103, USA.
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Rüb U, Gierga K, Brunt ER, de Vos RAI, Bauer M, Schöls L, Bürk K, Auburger G, Bohl J, Schultz C, Vuksic M, Burbach GJ, Braak H, Deller T. Spinocerebellar ataxias types 2 and 3: degeneration of the pre-cerebellar nuclei isolates the three phylogenetically defined regions of the cerebellum. J Neural Transm (Vienna) 2005; 112:1523-45. [PMID: 15785863 DOI: 10.1007/s00702-005-0287-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2004] [Accepted: 01/08/2005] [Indexed: 02/07/2023]
Abstract
The pre-cerebellar nuclei act as a gate for the entire neocortical, brainstem and spinal cord afferent input destined for the cerebellum. Since no pathoanatomical studies of these nuclei had yet been performed in spinocerebellar ataxia type 2 (SCA2) or type 3 (SCA3), we carried out a detailed postmortem study of the pre-cerebellar nuclei in six SCA2 and seven SCA3 patients in order to further characterize the extent of brainstem degeneration in these ataxic disorders. By means of unconventionally thick serial sections through the brainstem stained for lipofuscin pigment and Nissl material, we could show that all of the pre-cerebellar nuclei (red, pontine, arcuate, prepositus hypoglossal, superior vestibular, lateral vestibular, medial vestibular, interstitial vestibular, spinal vestibular, vermiform, lateral reticular, external cuneate, subventricular, paramedian reticular, intercalate, interfascicular hypoglossal, and conterminal nuclei, pontobulbar body, reticulotegmental nucleus of the pons, inferior olive, and nucleus of Roller) are among the targets of both of the degenerative processes underlying SCA2 and SCA3. These novel findings are in contrast to the current neuropathological literature, which assumes that only a subset of pre-cerebellar nuclei in SCA2 and SCA3 may undergo neurodegeneration. Widespread damage to the pre-cerebellar nuclei separates all three phylogenetically and functionally defined regions of the cerebellum, impairs their physiological functions and thus explains the occurrence of gait, stance, limb and truncal ataxia, dysarthria, truncal and postural instability with disequilibrium, impairments of the vestibulo-ocular reaction and optokinetic nystagmus, slowed and saccadic smooth pursuits, dysmetrical horizontal saccades, and gaze-evoked nystagmus during SCA2 and SCA3.
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Affiliation(s)
- U Rüb
- Institute of Clinical Neuroanatomy, J. W. Goethe University, Frankfurt/Main, Germany.
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40
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Abstract
According to the current state-of-art on the brainstem functional anatomy and reticular formation, authors believe that nucleus tractus solitarii (NTS) is the neural structure, which meets all the conditions of the hypothetical syncope generating, reflex centre. The afferent branch of this reflex arc represents information from different visceral sources including the brain itself. The efferent branch of this reflex arc is reticular activating system (RAS). The executive mechanism of syncope is deactivation of RAS done with the active engagement of NTS through solitarioreticular pathway (SRT) and parabrachial nuclear complex (PBC). The biological purpose of syncope would be resetting of the NTS in case of an unbearable vegetative input, which is code for triggering the mechanism described.
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Affiliation(s)
- Niko Zurak
- Department of Neurology, Clinical Hospital Centre Zagreb, Kispaticeva 12, 10 000 Zagreb,Croatia
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41
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Sarnat HB. Ontogeny of the reticular formation: its possible relation to the myoclonic epilepsies. Adv Neurol 2005; 95:15-22. [PMID: 15508911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Affiliation(s)
- Harvey B Sarnat
- Alberta Children's Hospital, Pediatrics (Neurology), Calgary, Alberta, Canada
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Ishimoto T, Chiba S, Omori N. Convulsive seizures induced by α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid microinjection into the mesencephalic reticular formation in rats. Brain Res 2004; 1021:69-75. [PMID: 15328033 DOI: 10.1016/j.brainres.2004.03.081] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2004] [Indexed: 11/22/2022]
Abstract
Effects of microinjections of a single 2 or 10 nmol dose of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) into the unilateral mesencephalic reticular formation (MRF) on behavior and on the electroencephalogram were examined in rats (n=30) over a 15-min period (Exp. 1); subsequent effects of sound stimulation with key jingling applied at 15, 30, and 45 min after the injection were observed (Exp. 2). The microinjections of a 2 nmol dose of AMPA (n=15) induced hyperactivity (15 of 15 rats) and running/circling (10 of 15 rats) in Exp. 1, and hyperactivity (5 of 15 rats) in Exp. 2. Moreover, the microinjections of a 10 nmol dose of AMPA (n=15) induced hyperactivity (15 of 15 rats), running/circling (13 of 15 rats), generalized tonic-clonic seizures (GTCS) (4 of 15 rats), and amygdala kindling-like seizures (AMKS) (8 of 15 rats) in Exp. 1; electroencephalographic seizure discharges were predominantly observed in the MRF during hyperactivity, running/circling and GTCS, while those predominantly observed in the amygdala were during AMKS. In Exp. 2, hyperactivity (15 of 15 rats), running/circling (14 of 15 rats) and GTCS (6 of 15 rats) were elicited by sound stimulation, although AMKS were not. The control group of rats (n=15) which received a single dose of saline microinjection into the unilateral MRF showed no behavioral or electroencephalographic changes in both Exp. 1 and 2. These findings suggest that potentiation of excitatory amino acid neurotransmission induced by AMPA injection into the MRF plays an important role not only in the development of hyperactivity, running/circling, GTCS and AMKS, but also in the development of audiogenic seizures.
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Affiliation(s)
- Takahiro Ishimoto
- Department of Psychiatry and Neurology, Asahikawa Medical College, Midorigaoka higashi 2-1-1-1, Asahikawa 078-8510, Japan
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Gordeev SA, Fedotova AV, Posokhov SI, Solov'eva AD, Veĭn AM. [A psychoneurophysiological evaluation of non-specific cerebral systems in patients with permanent autonomic disorders of psychogenic etiology during therapy]. Vestn Ross Akad Med Nauk 2004:40-3. [PMID: 15101208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
Fifteen patients with permanent vegetative disorders combined with a pronounced anxiety were examined before and after treatment by the Nott drug. The clinical-and-neurological technique, psychometric evaluation of cognitive functions and the neurophysiological method of acoustic cognitive induced potentials P300 were made use of. Before treatment, pronounced vegetative anxiety-related and cognitive disorders were observed in patients. A reliably decreased amplitude of the P300 peak was noted in patients versus healthy subjects while registering the cognitive induced potentials. After treatment, there was a reliably decreased severity of vegetative, anxious and cognitive disorders in patients; the P300 amplitude went up reliably. Supposedly, the changed P300 amplitude, as observed in patients with permanent vegetative disorders; denotes the malfunction in non-specific limbic-reticular brain structures. A growing P300-peak amplitude combined with the arrest of psychovegetative and anxious disorders and with an improvement of cognitive functions in patients due to therapy are indicative of a lower degree of the functional disintegration in the non-specific limbic-reticular brain structures. Finally, the method of endogenous induced P300 potentials can be used as a diagnostic tool in the objective evaluation of a condition of non-specific brain systems in patients with the psychovegetative syndrome; it can also be an objective criterion in the efficiency assessment of a conducted therapy.
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Abstract
An intrinsic function of the reticular activating system (RAS) is its participation in fight vs. flight responses such that alerting stimuli simultaneously activate thalamocortical systems, as well as postural and locomotor systems, in order to enable an appropriate response. The P50 midlatency auditory-evoked potential appears to be an ascending manifestation of the cholinergic arm of the RAS in eliciting changes in arousal state. Abnormalities in the manifestation of the P50 potential are present in disorders which include: (1) dysregulation of sleep-wake cycles; (2) abnormalities in reflex/postural, especially, startle, responses; and (3) malfunctions in flight vs. flight responses. In general, the P50 potential appears to be upregulated (increased amplitude and/or decreased sensory gating) in disorders which are marked by upregulation of RAS outputs (hypervigilance), and downregulated in disorders characterized by decreased RAS outputs (hypovigilance). Many of the disorders discussed have a developmental etiology and a postpubertal age of onset.
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Affiliation(s)
- Robert D Skinner
- Department of Anatomy and Neurobiology, University of Arkansas Medical Sciences, Little Rock, AR 72205, USA.
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Affiliation(s)
- Jaideep Kapur
- Department of Neurology, Box 800394, Health Sciences Center, University of Virginia, Charlottesville, VA 22908-0394, USA.
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Abstract
The brainstem trigeminal complex integrates somatosensory inputs from orofacial areas and meninges. Recent studies have shown the existence of a double representation of pain within the brainstem, at the level of both caudalis and oralis subnuclei. Noxious messages are mainly conveyed by C-fibers that activate the subnucleus caudalis neurons. These neurons in turn activate the subnucleus oralis whose neurons share similar features with the deep spinal dorsal horn neurons. In contrast with the nearness of the laminar organization of the dorsal horn, the vertical organization of the trigeminal complex offers an easier access for the study of segmental mechanisms of nociceptive processing. This model allowed us to show the existence of subtle NMDA-related mechanisms of segmental nocious processing. The trigeminal complex conveys nociceptive messages to several brainstem and thalamic relays that activate a number of cortical areas responsible for pain sensations and reactions. Cortical processing is sustained by reciprocal interactions with thalamic areas and also by a direct modulation of their pre-thalamic relays. The dysfunction of these multiple modulatory mechanisms probably plays a key role in the pathophysiology of chronic trigeminal pain.
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Affiliation(s)
- Radhouane Dallel
- Inserm E 0216, Neurobiologie de la douleur trigéminale, Faculté de chirurgie dentaire, 11, boulevard Charles de Gaulle, 63000 Clermont-Ferrand, France.
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Soroko SI, Dzhunusova GS. [Rearrangement of total electrical activity of the cerebral cortex and subcortical structures in experimental hypoxia]. Fiziol Cheloveka 2003; 29:5-12. [PMID: 12679985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
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Abstract
The knowledge of seasickness is as old as seafaring itself. In ancient times the Babylonians already reported on this malaise and on possible therapeutical measurements. The Babylonians, the advice of old sailors and modern pharmaceuticals have one thing in common. They have not been able to find a complete cure for motion disease. The interactions of the relevant cerebral structures are so complex that no drug is available which can interrupt this process definitively. The most important preventive measure is to develop strategies which lead to a quicker adaptation to movement.
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Affiliation(s)
- G Seydl
- Institut für Geschichte der Medizin, Universität Wien, Währingerstrasse 25, A-1090 Wien.
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Heidel KM, Benarroch EE, Gené R, Klein F, Meli F, Saadia D, Nogués MA. Cardiovascular and respiratory consequences of bilateral involvement of the medullary intermediate reticular formation in syringobulbia. Clin Auton Res 2002; 12:450-6. [PMID: 12598949 DOI: 10.1007/s10286-002-0075-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
We studied five patients with clinical and radiological evidence of syringobulbia (SB) to determine whether the distribution of lesions in relationship to the cardiorespiratory control networks in the medullary intermediate reticular zone (IRt) correlates with the presence of abnormalities in autonomic cardiovascular and respiratory control in these patients. All patients underwent high resolution MRI to characterize the size, volume and distribution of the SB lesions, cardiovascular autonomic function testing and polysomnography. One patient with bilateral IRt involvement at both the rostral and caudal medulla had orthostatic hypotension (OH), absent HR(DB), abnormal Valsalva ratio, exaggerated fall of BP during phase II and absent phase IV during VM, and a dramatic fall of BP during head up tilt; this patient also had severe obstructive sleep apnea (OSA) and exhibited BP drops during each respiratory effort. A second patient, with bilateral IRt involvement restricted to the caudal medulla, had less severe cardiovascular autonomic dysfunction but also exhibited severe OSA. The other three patients had small SB cavities sparing the IRt and had sleep apnea but no autonomic dysfunction. Autonomic dysfunction could not be related to the size of the syrinx or the degree of atrophy in the cervical spinal cord in any of the five patients. Bilateral involvement of the IRt by SB produces cardiovascular autonomic failure and sleep apnea. In patients with more restricted lesions, autonomic and respiratory dysfunction may be dissociated. Clinico-radiological correlations using high resolution MRI assessment of medullary lesions can provide insight into the central organization of cardiovascular and respiratory control in humans.
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Affiliation(s)
- K M Heidel
- Mayo Medical School, Mayo Clinic, Rochester, Minnesota, USA
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Abstract
Neurons within the medullary subnucleus reticularis dorsalis (SRD) of the rat convey selectively nociceptive information from all parts of the body. We have sought to define the neuronal networks that convey information from widespread noxious stimuli to the diffuse thalamocortical system and also modulate spinal outflow. The experiments, which were performed in rats, were designed to determine whether efferents from the SRD issue collaterals to the thalamus and spinal cord. Injections of the tracers fluorogold and tetramethylrhodamine-labelled dextran were centred stereotaxically in two areas that receive dense projections from the SRD: the cervical spinal cord and the lateral ventromedial thalamus (VMl), respectively. In other experimental series, SRD neurons were characterized electrophysiologically and individually labelled in a Golgi-like manner following juxtacellular iontophoresis of biotin-dextran. More than half reticulothalamic neurons within the SRD provided monosynaptic connections to the spinal cord. SRD neurons that responded to Adelta- or Adelta- and C-fibre activation from any area of the body had axons that gave both ascending and descending collaterals. Because the SRD innervates several areas involved in motor processing and receives strong, direct influences from several cortical regions, it could provide a structural basis for the processing of nociceptive and motor activities.
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Affiliation(s)
- L Monconduit
- INSERM, E216, Neurobiologie de la douleur trigéminale, Faculté de Chirurgie Dentaire, 11, Boulevard Charles de Gaulle, 63000, Clermont-Ferrand, France
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